| 摘要 |
PURPOSE:To attain freely the transmission/reception of a data between such as a transmitter of a differential pressure transmitter and of an electromagnetic flowmeter and a communication equipment by superimposing a digital signal on an analog signal to attain transmission/reception and also transmitting a digital signal including the own identification code from the transmitter. CONSTITUTION:Transmitters Tx1-Txn control individually a current value from a power supply section PS of communication equipment CE1-CEn connected to two-wire transmission lines La1, Lb1-Lan, Lbn by means of connectors selectively freely attachably and detachably and transmit the result as an analog signal. The communication equipment CEi receives the analog signal based on a terminal voltage of a resistor Rc inserted in series with the power supply section PS. The voltage of the power supply section PS of the communication equipment CEi is transmitted as a digital signal by being changed into a pulse form and received by a transmitter Txi. The Txi superimposes the digital signal upon receiving it onto the analog signal, changes the current value I into pulse form, transmits it as a digital signal including the own individual code, and the signal is received by the communication equipment CE. |
